The nature of an observed defect in cAMP metabolism, increased basal activity of adenylate cyclase, in Reye's syndrome, a toxic encephalopathy with fatty visceral changes, will be explored by the systematic analysis of the several components which sequentially mediate hormone action in adipocytes obtained by needle biopsy. Methods to be used include estimates of hormone-receptor sites, phosphoprotein phosphatase activity, cAMP-dependent protein kinase activity, cAMP binding characteristics and adenylate cyclase kinetic characteristics.